ENERGY-CHANNEL Conversion Table

(for FTOOLS 5.0.4, pca_e2c_e05v01.fits, and Epoch 5)

This table contains information about the channel-energy relationship
for RXTE PCA data for the four gain epochs (1-4) and the latest
calibration epoch (5) of the mission so far
(Epoch 1 = launch through 3/21/96; Epoch 2 = 3/21/96 - 4/15/96; Epoch
3 = 4/15/96 - 3/22/99; Epoch 4 = 3/22/99 - 5/12/2000; Epoch 5 = 5/13/00
-
present). In Epochs 1-4, the data were generated for the
full PCA with all detectors and layers added, using FTOOLS 5.0.4 and the
energy-to-channel file pca_e2c_e05v01.fits. For calibration Epoch 5,
defined by the time of loss of the propane layer in PCU 0,
the data were generated separately for PCU0 and for PCUs 1-4.
Note that Epoch 5 simply refers to the loss of propane for PCU0,
and does not imply a gain change for the PCA. If you have used earlier
versions of the response matrix generation tools, you will notice
small differences between your values and the values given here.
(The
FTOOLS 5.0 ,
FTOOLS 4.1 , and
FTOOLS 3.7
energy-channel conversion tables
are available for comparison.)

The PCA onboard electronics bin up the channels differently depending on
which configuration has been requested. The first column contains the
ORIGINAL (or absolute) channels, while the second column contains the
channel binning for Standard 2 data (which is the type of data most RXTE
analysts start on). Subsequent columns give the maximum energy bound for
each channel.

IMPORTANT NOTES:

Remember that when you perform channel selection, the extractors require
you to supply the ORIGINAL channel boundaries, regardless of the mode of
data you are analyzing (Std2, Binned, Event, GoodXenon etc). For further
details see the ABC guide, or the cookbook recipe "Creating and plotting
light curves, hardness ratios and color-color diagrams."

The information in this table is useful for most cases, but
should be considered only approximate (within a few percent). If you
are performing analysis for which the exact values of the energy
boundaries are critical, or if you are analyzing data from separate
layers and detectors, you should generate a response matrix for your
particular dataset and examine the channel-energy information
contained in the first extension of the FITS file.

Note that the response matrix generator in FTOOLS 4.1 and higher now
accounts for the slow gain drift in the PCA. This gain shift amounts
to ~ 1 % over two years. The Epoch 3 and 4 values given in the table below
are computed for the beginning of each epoch.